JPH01217164A - Multi-chamber type airconditioner - Google Patents

Abstract

PURPOSE:To obtain a pleasant airconditioning state, by calculating the degree of subcooling of refrigerant by using a condensation temperature detector of a refrigerant and data transmitted from a temperature detector before a liquid refrigerant transferred into a room unit passes through a motordriven expansion valve and setting the opening of said expansion valve. CONSTITUTION:A control unit 14 takes in a condensation temperature of a refrigerant from a temperature detector 12 and temperature data transmitted from a temperature detector 13 before passing through a motor-driven expansion valve for a liquid refrigerant, and calculates the degree of refrigerant subcooling equivalent to each unit in the operation room based on the difference in the detected data. When the control unit judges that the average degree of refrigerant subcooling is greater than a specified value and the circulation quantity of refrigerant in a refrigerant operation cycle is maintained, the control unit sets the opening of motor-driven expansion valves 9b and 9c equivalent to a suspended unit so that a small amount of refrigerant may flow into the suspended indoor unit based on the drive of a pre- expansion valve by way of a control signal output device 15, and prevents the refrigerant from becoming accumulated in the suspended indoor unit. Moreover, when the control unit judges that the average degree of refrigerant subcooling is smaller than the specified value and the specified circulation quantity of refrigerant is not maintained, the control unit sets the opening of the motor-driven expansion valves 9b and 9c to a specified opening greater than the above value, draws out the refrigerant present from the suspended indoor unit and maintains the specified circulation quantity of refrigerant to the unit in the operation room.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heat pump type multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit.
In particular, it relates to surplus refrigerant control when any indoor unit is stopped.

"Prior Art" 4 Tonbu Publication = Showa-- As described in Japanese Patent Publication No. 61-128069, a conventional device is used to control surplus refrigerant when any indoor unit is inactive in a multi-room air conditioner. As a means, an electric valve is provided in the outdoor unit measured branch pipe connected to each indoor unit, and the electric valve corresponding to the indoor unit is set to a predetermined opening degree depending on the number of operating indoor units, and furthermore, The electric valve is corrected so that the refrigerant temperature of each branch pipe to be measured becomes the average refrigerant temperature of each branch pipe to be measured at a predetermined opening degree, and the electric valve corresponding to the pause unit is set to a small opening degree so that the refrigerant is in the pause unit. In addition, if the refrigerant temperature of the measured branch pipe corresponding to the idle unit is lower than the temperature of each measured branch pipe,
It is proposed to prevent refrigerant from accumulating in the pause unit by opening the electric valve corresponding to the pause unit more slightly.

[Problem to be solved by the invention]

The main purpose of the above conventional technology is to remove the refrigerant accumulated in the idle unit, and it is insufficient in terms of optimizing the amount of refrigerant circulated in the operating refrigerant cycle, which varies depending on the indoor load of the operating unit, etc. Due to this lack of consideration, the heat exchanger in the driver's cabin unit was not able to fully demonstrate its performance, and there was a problem that comfortable air conditioning could not be obtained.

An object of the present invention is to solve the above-mentioned problems, perform surplus refrigerant control according to the state of the operating cycle, make the indoor heat exchanger work efficiently, and obtain comfortable air conditioning conditions.

[Means to solve the problem]

The above purpose is to provide a detector to detect the condensation temperature of the refrigerant during heating operation, a detector to detect the temperature of the liquid refrigerant sent from each indoor unit to the outdoor unit before passing through the electric expansion valve, and a detector to detect the temperature. a control device that calculates the degree of subcooling of the refrigerant from temperature data from the device and determines the control content for the expansion valve according to a program inputted in advance; and a control signal that drives the expansion valve according to the determined control content. An output device is installed, and when any indoor unit is at rest,
In the invention set forth in claim 1, if the average value of the degree of subcooling of the refrigerant on each driving indoor unit side calculated from the data from the temperature sensor is larger than a predetermined value, a small amount of the refrigerant is stopped. pulsating and setting the expansion valve corresponding to the idle indoor unit from the control device through the control signal output device to a predetermined opening such that the flow flows through the indoor unit, and when the average value of the degree of supercooling is smaller than a predetermined value; This is achieved by setting the predetermined opening degree to be larger than the predetermined opening degree when the opening is large. Further, in the invention of claim 2, the average value of the degree of supercooling of the refrigerant is smaller than a predetermined value, and even if the opening degree of the expansion valve is set to a predetermined degree as in claim 1, Note that if the average value of the degree of subcooling of the refrigerant does not become larger than the predetermined value within a predetermined period of time, a new larger predetermined opening degree is set for the expansion valve of the suspension unit. This is achieved by setting a large opening.

[Effect]

In the invention set forth in claim 1, the control device receives data on the condensation temperature of the refrigerant and the temperature of the liquid refrigerant before passing through the electric expansion valve from the temperature detector, and based on the difference between the data, the refrigerant corresponding to each operating room unit is determined. If the degree of subcooling is calculated and the average degree of subcooling of the refrigerant is greater than the predetermined value, and it is determined that the amount of refrigerant circulating in the refrigerant operation chamber is secured, a small amount of the electric expansion valve corresponding to the idle unit is activated. The pre-expansion valve is set by driving the pre-expansion valve through the control signal output device so that the pre-expansion valve is opened to a predetermined degree so that the refrigerant flows through the idle indoor unit.This prevents refrigerant from accumulating in the idle indoor unit and also reduces the degree of subcooling of the refrigerant. If the average is smaller than the predetermined value and it is determined that the refrigerant circulation amount during the refrigerant operation cycle is not secured, the electric expansion valve corresponding to the idle unit is set to the predetermined value when it is determined that the refrigerant circulation amount is secured. Set as a predetermined opening larger than the opening.

The effect of removing the refrigerant accumulated in the idle indoor unit and ensuring the amount of circulation to the operating indoor unit can be obtained.

In the invention of claim 2, the effect of the invention of claim 1 can be obtained, and further refrigerant circulation to the driver's indoor unit is required due to changes in the indoor load, so that the refrigerant on the driver's indoor unit is If the average degree of supercooling does not return to the predetermined value within a predetermined time even after implementation of the invention set forth in Item 1, a new, larger predetermined opening degree is set for the electric expansion valve corresponding to the idle indoor unit. By increasing the opening degree of the expansion valve in multiple steps, it is possible to quickly ensure the amount of refrigerant circulating to the indoor unit.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

As shown in Figure 1, this air conditioner has a configuration in which three indoor units are connected to one outdoor unit. A heat exchanger 4 and a receiver 5 provided in the refrigerant liquid side main pipe 6 are provided. In addition, three branch pipes 10a, 10b, l to be measured branched from the main pipe 6 on the refrigerant liquid side.
Forward and reverse flow electric expansion valves 9a, 9b, 9 for each oc.
C is provided. The indoor unit side is equipped with respective indoor heat exchangers 8a, 8b, and 8c, and by connecting each device in the outdoor unit and each device in the indoor unit with piping as shown in the diagram, a heat pump type refrigeration cycle can be established. It consists of In addition, the outdoor unit includes a detector 12 that detects the refrigerant condensation temperature in a condensing pipe led from the refrigerant discharge pipe, and electric expansion valves 9a, 9b, 9 during heating operation.
Detector 13a detects the refrigerant temperature before the pressure drop due to c.
, 13b, 13c A control device 14 that is connected to the detector and processes the detected contents according to a pre-input program; and electric expansion valves 9a, 9b under the command of the control device 14;
A control signal output device 15 for outputting the expansion valve opening amount is provided at 9c.

FIG. 2 shows the relationship between the degree of subcooling of the refrigerant and the opening degree of the pause unit expansion valve in the first embodiment, and FIG. 3 shows the control flow in the first embodiment. The relationship between the degree of subcooling of the refrigerant and the opening degree of the pause unit expansion valve in the example, and FIG. 5 shows the flow of control in the second example. The operation will be explained using the above configuration.

(First Example) During heating operation, when only the indoor unit with the indoor heat exchanger 8a is operated, the refrigerant gas from the compressor 1 passes through the four-way valve 2, the gas side main pipe 7, and the gas side branch pipe 11a to enter the room. It is sent to the heat exchanger 8a, condensed, and sent to the outdoor heat exchanger 4 via the electric expansion valve 9a, the branch pipe 10a, the liquid side main pipe 6, and the receiver 5, and evaporated into gas. It passes through and returns to compressor 1.

Further, the electric expansion valve 9a corresponding to the operating indoor unit performs PID control based on the degree of refrigerant superheating, and the electric expansion valves 9b and 9c corresponding to the idle indoor unit are in the initial first stage state of idle, as shown in FIG. is set to b pulse at ,
A small amount of refrigerant is flowed to prevent refrigerant from accumulating in the idle unit.

If heating operation is performed in this state, the expansion valve opening of the idle unit is currently opened by b pulses, but due to the indoor temperature, piping connection status, etc., more refrigerant accumulates in the idle unit, and the operating unit The refrigerant will not circulate sufficiently. As a means of detecting this state, first detect the condensation temperature using the detector 12 (step 16 in Fig. 3).
, the temperature in front of the expansion valve corresponding to the unit in the driver's room is detected by the detector 13a (step 17). next.

The control device 14 averages the temperatures in front of the expansion valves corresponding to the operating indoor units, but in this embodiment, the operating units are
Since the temperature is only in the room, the difference between the temperature detected by the detector 13a and the condensation temperature is determined, and the degree of supercooling of the refrigerant in the operating cycle is calculated (step 18).

Then, if the refrigerant subcooling degree satisfies a certain predetermined value,
The amount of refrigerant during the refrigerant circulation cycle is determined to be appropriate and controlled so that the degree of refrigerant supercooling calculated from a predetermined set value a determined in advance through experiments or the like is increased. For example, in FIG. 2, if the degree of refrigerant subcooling f calculated at time d falls below the set value a, the control device 14 determines in step 19 of FIG. In order to increase the refrigerant (step 20 in FIG. 3), the accumulated refrigerant is discharged from the idle unit. Thereafter, data is acquired from the detector at regular sampling intervals, and steps 16 to 20 in Figure 3 are repeated each time.
When the refrigerant subcooling degree f returns to the set value a as at time e in FIG. 2, the process proceeds to step 21 through step 19 in FIG. 3, and the expansion valve opening degree of the pause unit is returned to b pulse.

By controlling as described above, it is possible to maintain the degree of subcooling of the refrigerant above a certain level, the amount of refrigerant circulation is maintained at an optimum level, and a proper and stable refrigeration cycle can be obtained.

(Second embodiment) This embodiment has completely the same components as the first embodiment,
The operation will be explained with reference to FIGS. 4 and 5.

In the first embodiment, even if the expansion valve opening degree of the pause unit is set to C, if the refrigerant supercooling degree still does not return to the set value a, or if it takes a long time to return, the refrigerant supercooling degree may be further increased. In order to increase the stability of the cooling degree, the following control is performed. In other words.

In Fig. 4, the degree of subcooling f of the refrigerant reaches the set value a at time j.
If the degree of subcooling f is below the set value, the opening degree of the expansion valve of the pause unit is first increased from b to C as in the first embodiment, and the refrigerant supercooling degree f is still at the set value at the time scale in FIG. 4 after a predetermined time m minutes. When it is below 'a, the opening degree of the pause unit expansion valve is increased to h pulse (step 24.25 in FIG. 5). In addition, if the refrigerant supercooling degree f is lower than the set value a at the time scale point in Figure 4 after m minutes have elapsed even after the pause unit expansion valve opening degree has been increased to h pulse, the pause unit expansion valve opening degree is further increased to i. increase. (Steps 26 and 27 in Fig. 5) In this embodiment, the opening degree i is the final opening degree and continues until the refrigerant supercooling degree f returns to the set value a, and after the return, the initial suspension unit expansion valve is opened. (Step 21 in Figure 5)
. Incidentally, steps 22 and 23 in FIG. 5 are determinations on the control program to continue when the suspension unit expansion valve opening degree is h or i.

By controlling as described above, it is possible to reliably and quickly maintain the degree of refrigerant subcooling above a certain level, and the amount of refrigerant circulation can be stabilized reliably and quickly.

A proper and stable refrigeration cycle can be obtained.

Note that the present invention is not limited to this embodiment, and for example, the condensation temperature when calculating the degree of subcooling of the refrigerant can be directly measured from the indoor heat exchange port without changing the gist. It can be modified in various ways within the range.

〔Effect of the invention〕

According to the present invention, in a multi-room air conditioner, even if any indoor unit among a plurality of indoor units is stopped, a refrigeration cycle can be formed with an appropriate refrigerant circulation amount according to the number of indoor units in operation. This has the effect of providing a comfortable air-conditioned space.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle system diagram showing one embodiment of the multi-room air conditioner of the present invention, FIG. Figure 3 is the first
FIG. 4 is a diagram showing the relationship between the degree of subcooling of the refrigerant and the opening degree of the expansion valve of the pause unit in the second embodiment, and FIG. 5 is a flowchart of the control in the second embodiment. . 1...Compressor 4...Outdoor heat exchanger 8a, 8
b, 8c... Indoor heat exchanger 9a, 9b, 9c...
・Electric expansion valve 12, 13a, 13b, 13c...
・Temperature detector 14...Control device 15...Control signal output device 16-27...Contents of control processing in the first and second embodiments 11th lS--1; ; 8 jin ≧ 17 sag second
eye

Claims (1)

[Claims] 1. One outdoor unit consisting of a compressor, an outdoor heat exchanger, a four-way valve, etc. whose capacity can be controlled by changing the input frequency, and an indoor heat exchanger, etc. via their respective connection pipes. In a multi-room air conditioning system that is equipped with multiple indoor units consisting of a heat pump type refrigeration cycle, each of the multiple liquid-side branch pipes branched from the liquid-side main pipe of the outdoor unit is equipped with an electric expansion valve. At times, there is a detector that detects the condensation temperature of the refrigerant, a detector that detects the temperature of the liquid refrigerant sent from each indoor unit to the outdoor unit before passing through the expansion valve, and temperature data from these temperature detectors. A control device that calculates the degree of subcooling of the refrigerant and determines control details for the expansion valve according to a pre-input program, and outputs an opening amount to the expansion valve according to the determined control details to drive the expansion valve. A control signal output device is provided, and when any indoor unit is at rest, if the degree of subcooling of the refrigerant in the operating indoor unit calculated from the data from the temperature sensor is greater than a predetermined value, a small amount of refrigerant is The expansion valve is set to a predetermined opening degree by the control device and the control signal output device so that the refrigerant flows through the rest unit, and when the degree of subcooling of the refrigerant is smaller than a predetermined value, the refrigerant flows further toward the rest unit than when it is larger. A multi-room air conditioner characterized in that by setting the expansion valve to a predetermined opening degree that allows fluid to flow, the degree of supercooling on the driver's indoor unit side is stabilized and an optimal amount of refrigerant circulation to the driver's indoor unit can be obtained. Device. 2. If the degree of subcooling of the refrigerant is smaller than the predetermined value and the degree of subcooling of the refrigerant does not become larger than the predetermined value within the predetermined time even if the opening degree of the electric expansion valve is set to the predetermined value, the refrigerant is further transferred to the stop unit. A new larger predetermined opening degree is set for the expansion valve so that the refrigerant flows, and when the degree of subcooling of the refrigerant does not reach a predetermined value or more within a predetermined time, a new larger predetermined opening degree is set for the expansion valve. The multi-chamber system according to claim 1, wherein the degree of supercooling of the refrigerant is controlled to reach a target predetermined value at an early stage by increasing the opening degree of the expansion valve in multiple steps. Shape air conditioner.